Tandem wedge expansion unit for mine ceiling support



Feb. 22, 1966 TEEPLE, JR 3,235,146

TANDEM WEDGE EXPANSION UNIT FOR MINE CEILING SUPPORT Filed Nov. 13, 1961 2 Sheets-Sheet l INVENTOR FRANK ATEEPLEQE Feb. 22, 1966 F. A. TEEPLE, JR 3,236,146

TANDEM WEDGE EXPANSION UNIT FOR MINE CEILING SUPPORT Filed Nov. 13, 1961 2 Sheets-Sheet 2 4'2 INVENTOR FEAHK A EEPLE,A2

i. f 5% 42 :59 3g 2 51 ATTORNEYS 3,236,146 TANDEM WEDGE EXPANSION UNIT FOR MINE CEILEN G SUPPORT Frank A. Teeple, J13, Huntington, W. Va., assignor to H. K. Porter Company, Inc Pittsburgh, Pa., a corporation of Delaware Filed Nov. 13, 1961, Ser. No. 151375 1 Claim. (Cl. 8576) The invention relates generally to the art of mining and primarily seeks to provide a novel expansion unit for anchoring the roof suspension bolts by which mine ceiling or roof portions are supported.

Roof suspension bolts, or as popularly called, roof bolts, are now widely used. In the use of these bolts, holes are drilled vertically or sometimes at an angle, upwardly into the mine roof or ceiling, and supporting bolts directed through supporting plates or bars engaged with the roof or ceiling are inserted in the holes and anchored therein for securely supporting the engaged roof portions and portions adjacent thereto. The anchoring of the bolts is effected by employment of expansion units inserted in the roof bores and through which the bores are threaded, means being included which are effective upon threading home of the bolts to expand the units and cause them to firmly grip the wall portions defining the bolt receiving bores. It is a purpose of the present inven tion to provide a novel form of expansion unit which can be easily and economically manufactured, and which is subject to being inserted into a receiving bore with great facility and capable of very securely anchoring a rod threaded therethrough.

An object of the present invention is to provide an expansion unit of the herein described character including longitudinally disposed and opposed laterally spreadable shell wings shaped to present a generally cylindrical exterial surface for engagement in a mine ceiling bore, an expander plug means having a threaded longitudinal bore therethrough and movable longitudinally between the shell wings, the wings and the plug means having cooperating camming surfaces arranged in tandem relationship and operatively efiective when the plug means is longitudinally moved between the shell wings, and a bolt threaded through the expand-er plug means for longitudinally moving the expander plug means relative to the shell wings to bring about a lateral spreading of the wings.

Another object of the present invention is to provide an expansion unit of the herein described character in which opposed longitudinally disposed shell Wings shaped to provide a generally cylindrical shell enclose the expander plug means so as to form an assembly which will not come apart when subjected to rough handling as in mining use.

Another object of the present invention is to provide an expansion unit of the herein described character including a unitary expander plug structure having thereon pairs of wedge shaped projections, the projections of each pair being arranged in tandem relation, enclosing laterally expandable shell wings shaped to cooperatively engage with the tandem wedge shaped projections so that even distribution of shell wing forces against bore defining walls may be quickly accomplished by a relatively small longitudinal travel of the expander plug relative to the shell wings.

Another object of the present invention is to provide an expansion unit of the herein disclosed character including a unitary expander plug structure having thereon pairs of wedge shaped projections, the projections of each pair being arranged in tandem relation, the wedge projections being relatively wide and of steep converging slope, enclosing laterally expandable shell wings shaped to co- States Patent operatively engage with the tandem wedge shaped projections so that even distribution of shell wing forces against bore defining walls may be quickly accomplished by a relatively small longitudinal travel of the expander plug relative to the shell wings.

Still another object of the present invention is to provide for use in an expansion unit of the herein disclosed character an expander plug having a generally cylindrical body, an axial threaded bore extending therethrough for receiving a supporting bolt, and wedge shaped projections f(1)rm6d on the body arranged in tandem relation therea ong.

Still another object of the present invention is to provide for use in the herein disclosed expansion assembly an expansion shell comprising opposed wings which when longitudinally disposed in opposed relation present a generally cylindrical configuration to surrounding mine ceiling bore defining walls, each wing being provided with integrally connected wing sections and each section being defined by divergent edges and adapted to present opposed camming surfaces for engagement by an enclosed expander plug means having Wedge projections thereon and disposed for engagement between the opposed camming surfaces.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawings.

In the drawings:

FIGURE 1 is a top view of the herein described novel shell and expansion unit.

FIGURE 2 is a longitudinal sectional view, partly in side elevation, showing the expansion unit inserted in a mine ceiling bore and illustrating the initial contact of the lower wedge projections with the adjacent wing edges of the shell and the initial bearing point at which the shell and the ceiling bore defining walls contact.

FIGURE 3 is a side elevational view of the expansion unit of FIGURE 2 and turned degrees, the unit receiving bore being shown in longitudinal section.

FIGURE 4 is a horizontal sectional view taken on the line 4-4 on FIGURE 2.

FIGURE 5 is a horizontal sectional view taken on the line 5-5 on FIGURE 2.

FIGURE 6 is a plan view of the expander shell in blanked form.

FIGURE 7 is a side elevational view of the upper wedge plug element of FIGURES 2 and 3 and looking toward one of its Wedge projections and its undercut camming surfaces.

FIGURE 8 is a bottom plan view of the wedge plug element of FIGURE 7.

FIGURE 9 is a side elevational view and part longitudinal section of the upper wedge plug element of FIG- URES 4 and 8, the section being taken along line 99 of FIGURE 8.

FIGURE 10 is a side elevational view of the lower wedge plug element of FIGURES 2 and 3 and looking toward one of its wedge projections and its undercut camming surfaces.

FIGURE 11 is a side view of the lower wedge plug element of FIGURE 10 turned 90 degrees, a portion thereof being shown in section.

FIGURE 12 is a plan view illustrating a wedge plug structure having wedge projection pairs as shown in FIG- URES 2 and 3, the plug structure being formed in one piece.

FIGURE 13 is a side elevational view of the one piece wedge plug of FIGURE 12, the plug structure being 3 shown partially in longitudinal section along the line 1313 of FIGURE 12.

FIGURE 14 is a side elevational view of the one piece wedge plug structure of FIGURE 13 and looking toward one pair of the tandem wedge projections and their undercut camming surfaces.

In an example of embodiment of the herein disclosed invention, illustrated in FIGURE 2, a section of the mine roof ceiling as shown at 5 is drilled to provide a hole 6 in which the expansion unit, generally designated 7, is inserted. The expansion unit serves as anchoring means for the bolt 8 with a head 9 which, in turn, serves to support the plate 10 in load bearing relationship to the mine wall ceiling 11, and to thereby support the ceiling.

The improved expansion unit generally designated 7 includes an integral shell generally designated 12 and an expander plug means 13 having projecting wide angle wedges in tandem relation that may be formed separately and connected thereto or formed as part of the plug itself. When the individual parts comprising the expansion unit are assembled the expander plug means is held within the shell against inadvertent fall-out in a manner to be described hereinafter and as shown in FIGURE 2. The expander plug structure may comprise two wedge elements or units separably mountable on the bolt, as shown in FIGURES 2, 3, 4, 5 and 7 to 11, or the expander plug may constitute a one-piece unit as in FIGURES 12-14.

Although the invention will be described as consisting of two wedge units or sets in tandem relation and in cooperation with an expansion shell shaped to provide two sets of mating edges which are in contact with edges of the wedge projections arranged in tandem relation, it should be understood that such an arrangement is merely representative, and that a number of wedge units greater than the two pairs or setsherein illustrated in detail may be employed.

The shell 12, illustrated in FIGURES 2, 3 and 6, preferably is formed from a fiat metal blank as shown in FIGURE 6 and then shaped into a generally cylindrical configuration within which the expander plug means in the form of separate wedge pair units or an integral plug unit with multiple wedge pairs will be enclosed against fall out as best shown in FIGURE 2.

The shell 12 includes wings generally designated 14 and centrally connected by a ring-like portion 15 which is traversed centrally by an abutment bar 16, the wings 14 being integrally connected to the ring-like portion 15 by relatively narrow connecting members or straps 17. The wings 14 are each shaped to include outwardly flared longitudinally aligned upper and lower sections 18 and 19. The upper wing sections 18 are disposed proximal to the ring-like portion 15 and extend from the connecting straps 17 within outwardly divergent lines and each is fashioned to present a generally trapezoidal configuration. The lower wing sections 19 are connected to and extend from the upper wing sections 18, and, as will be apparent from FIGURE 6, each wing section 19 alsopresents a generally trapezoidal configuration.

The side edges 20-21 of the wing sections 18, 19 are camming surfaces and form symmetrically divergent sides of the respective generally trapezoidal wing configurations. Toward the lower extremities of the lower shell sections 19, the lateral edges 21 of wing sections 19 may be shaped in parallel relation to each other as indicated at 22.

The expander plug means may be either cast or forged as an integral structure having upper and lower sets of wedge extensions thereon in tandem, as in FIGURES 13 and 14, or may be composed of separate elements as in FIGURES 7 and 10. Referring first in detail to the cast or forged plug of FIGURES 13 and 14 it will be observed that this expander plug is generally designated 23 and includes a generally cylindrical body 24 having a threaded bore 25 formed axially therethrough and adapted to receive the anchoring bolt 8. At its upper portion the body portion 24 is provided with wedge-shaped projections 4 27. The plug 23 also includes two side leg dependencies 26, and these, like the body 24, are equipped with wedge shaped projections 28. The wedge shaped projections 27, 28 are defined at their lateral edges with undercut camming surfaces 29-30, respectively.

Referring now to the details of the expander unit composed of separate elements as in FIGURES 2 and 7 to 10, the member disposed uppermost is designated 31 while the lower member is designated 32. The member 31 is formed in the general configuration of the upper part of member 23, that is to say, the member 31 includes a generally cylindrical body 33 having a threaded bore 34 formed axially therethrough and adapted to receive the anchoring bolt 8.

The upper member 31 is further provided with wedge shaped projections 35 which extend from body portion 33. The lower wedge member 32 corresponds to the lower portion of the one-piece expander plug 23 and includes a generally cylindrical body portion 36 having an axial bore 37 therethrough and is further provided with wedge shaped projections 38. It should be noted that the wedge shaped projections 38 of the member 32 and the wedge shaped projections 28 of the member 23 are cut otf short of a converging wedge point and thereby form flush or flattened terminals designated 39, 40, respectively. The wedge shaped projections 35 of member 31 and the wedge shaped projections 38 of member 32 are defined at their lateral edges with undercut camming surfaces 41, 42, respectively.

As is apparent from FIGURE 2, the opposed shell wings contact the tandemly disposed sets of wedge shaped extensions of the expander plug means along their camming surfaces and thus prevent the expander plug means 13 from rotating upon the turning of the supporting bolt 8. Thus upon tightening the supporting bolt 8 the expander plug means 13 can only move longitudinally between the opposed shell wings to laterally spread or expand the wings into gripping contact with the mine ceiling bore, defining walls. With either form of the expander means the tandemly disposed sets of Wedge shaped extensions cooperating with the opposed shell wing edges prevent the sets of extensions from rotating relative to each other and assures that the separate element form of the expander plug means functions as an integral unit. Therefore since the operation of the expansion unit is generally the same in both forms of the expander plug means, their Operational aspects will be described together.

In conditioning the expansion unit for use, the blank of FIGURE 6 is bent about its central ring-like portion 15 and the center abutment bar 16 thereof to embrace the expander plug means 13 as illustrated in FIGURES 2 and 3, and preferably at the same time, during this final conditioning of the shell, the flat wings 14 may be shaped into arcuate cross-section so that their lateral edges overlie the expander plug 23 or plugs 31, 32 and oppose the outwardly presented sets of wedge projections so that opposed camming edges 29-20, 41-20 and 30-21, 42-21 present themselves in working relationship. Also at this time, there is provided a high point or area of initial ceiling bore contact at 43 approximately between the tandemly arranged sets of wedge projections 27, 28 or 35, 38.

As can be seen by reference to FIGURES 3 and 4, when the shell blank is shaped about the expander plug means 23 or 31, 32 the expander plug means becomes slidably engaged between the opposed camming surfaces 20, 20 and 21, 21 of said shell. Thus, by reason of the inter-engagement of camming edges 29-20, 30-21 or 41-20, 42-21, the expander plug means is held within the shell assembly and the assembled unit cannot be made to fall apart.

The cooperating threaded bolt 8 is then inserted through the ceiling supporting plate 10 and threadably connected with the internal bore 25 or 34 of the expander plug means, whereupon the expander unit is inserted in the mine ceiling bore 6 in the manner illustrated in FIGURE 2. The initial grip of the shell in the bore hole is accomplished through the spring action of the shell 12 which is slightly compressed upon entry of the expansion unit into the bore hole, that is, the shell wings 14 will be forced further towards each other by the bore defining walls. As previously stated the furthest lateral extent of the assembled shell is at points 43, and it is therefore at these points that the initial grip is accomplished. Upon tightening of the bolt 8 and contact of its threaded end with the abutment bar 16, the expander plug means will be forced in a longitudinal direction, and because of the cooperative engagement of the wedging or camming surfaces 29-20, 30-21 or 41- 20, 42-21, the wings 14 of the shell member 12 will be laterally spread apart about their narrow strap connection 17 and will be caused to firmly and securely anchor the expansion unit and the supporting ceiling plate in the desired manner.

It can be seen that the lower edge sets of wedge shaped projections 28, 38 will present their flush terminals 39, 40 for initial contact with the generally cylindrical shell member 12 at points 44. Initial gripping contact between the ceiling bore hole and the shell assembly is at point 43 as previously described, noting that the wedge shaped projections 28, 38 are more steeply shaped, that is, the lateral edges 30, 42 of wedge-shaped projections 28, 38 define a smaller included angle than an included angle defined by the camming edges of the longitudinally extending diverging shell wing edges 21. Thus on the initial longitudinal movement of the expander plug means 13, the lower portions of shell wing section 19 by the force applied thereto at points 44 by the flush terminals 39, 40 are laterally spread apart and thus effect an initial bore gripping force at points 43 located between the tandem sets of wedge projections. As is best shown in FIGURE 2, the camming surfaces on the upper set of wedge projections 35 are initially spaced from the wing sections 18 and function only after the initial gripping has been completed at points 43.

Upon continued longitudinally movement of the expander plug means the tandemly disposed wedges, moving in unison, will through their camming surfaces 29, 30 or 41, 42 will force the shell wings laterally apart and into engagement with the ceiling bore defining walls so as to firmly secure and anchor the expansion assembly therein. It is to be understood that prior to said continued longitudinal movement of the expander plug means and during its initial movement, the shell wing sections 19 are initially slightly laterally spread and the Wedge shaped projection 28 or 38 is presented therebetween for full camming contact of surfaces 30-21 or 42-21. When the full extent of the lateral expansion of the wings has been completed so as to firmly anchor the expansion assembly, the bearing forces exerted upon the bore defining walls will be evenly distributed throughout the longitudinal extent of the opposed shell wings.

By providing relatively wide and quickly divergent wedge projections arranged in tandem, the evenly distributed engagement of the wings with the bore defining walls is effected more quickly than could be accomplished with a single set of wedge shaped projections. A single set of wedge projections, by necessity, would have to be of greater longitudinal extent and more gently tapered to accomplish even load distribution and then only through a considerably longer longitudinal travel of the expander plug means between the opposed shell wings.

It can be seen that by providing the camming edges 29, 30 and 41, 42 with undercut surfaces, best shown in FIGURES 7, 10 and 14 that an interlocking of said edges and the cooperating camming edges on the shell is assured. This prevents the outward deflection of the shell wing edges beyond the periphery of the engaging expander plug wedge projections. It will also be evident that such an arrangement distributes the forces upon the wedge projections caused by the expansion of the shell edges to be distributed in a circumferential or tangential direction to the threaded body portion of the expander plug means, thereby to avoid radial compressive straining of the expander plug-means and deformation of its threads such as might cause locking of the threads about the engaged bolt 8. This assures that there can be recovery of all bolts 8 and plates 10 which may be desired to be removed after the working of a particular mine room. Thus all hardware except for the expendable expansion unit itself, may be recovered thereby effecting a substantial cost savings.

It is also desirous to so shape the camming shell edges to generally correspond to the undercutting of the plug wedges thereby emphasizing the interlocking relation .of such as shown at 45 in FIGURE 5, if desired.

It will also be apparent that the expander plug means is constantly guided within the enclosing shell as it is downwardly forced by the turning of the bolt 8 and that therefore no disalignment between the expander plug means and the shell can take place.

In the integral plug form of the expander plug means the side leg dependencies 26 will, by the presentation of their undercut wedge shaped extensions 28 to the laterally expanding opposed shell wings be subjected to a lateral spreading force upon tightening of the supporting bolt 8 which if of sufficient strength, will laterally spread the leg dependencies 26 out of longitudinal alignment with their body portions 24. Such a lateral expansion or spreading apart of the leg dependencies 26 forces them into gripping engagement with the mine bore defining walls and thus provides for more equal circumferential distribution of the anchoring pressure exerted upon the bore defining walls.

While preferred forms and part arrangements have been shown in illustrating the invention, it is to be clearly understood that various changes in details and part arrangements may be made without departing from the spirit and scope of the invention as defined in the appended claim.

I claim:

An expansion unit for use in a bore, said unit comprising a shell, a bolt and an expander plug, said shell comprising opposed longitudinal wings integrally connected at upper extremities thereof by an abutment bar disposed for engagement with said bolt and free of one another at lower end extremities, said wings having upper and lower sets of opposed downwardly converging camming edges in tandem relation; said expander plug having upper and lower sets of wedge-shaped radial projections disposed between respective ones of said upper and lower sets of camming edges for expanding said shell into engagement with said bore, said expander plug having a threaded bore formed therein for cooperating with threads on said bolt; said lower set of projections being in engagement with said lower set of camming edges, and said upper set of projections being spaced above said upper camming edges, whereby said unit is initially expanded at said lower end extremities; said set of wedge-shaped projections having angularly disposed lateral edges defining a first included angle, said lower set of camming edges being disposed to define a second included angle, said first included angle being smaller than the said second included angle; each projection of said lower set of wedge-shaped projections having a terminal portion for providing initial point-contact engagement between said lower set of camming edges and said lower set of wedgeshaped projections to spread said wings at the lower end extremities prior to engagement of the upper set of projections with the upper camming edges.

(References on following page) References Cited by the Examiner UNITED 2,753,750 7/1956 Dempsey 8576 3,115,056 12/1963 Teeple.

T STATES PATEN S FOREIGN PATENTS B aker.

754,482 8/1956 Great Britain. Clements. 5 Devlin 85 -75 EDWARD C. ALLEN, Primary Examiner. Pleister. CARL W. TOMLIN, Examiner. 

